Invincible Oscar
While playing the game, press Select, then hold L1 and press X, Circle, X, Left(2), Square, R1, Down, Square(2).

Two extra Clams and fame
While playing the game, press Select, then hold L1 and press Circle(2), X(2), Circle, X, Circle(2).

Attack mode on at all times
While playing the game, press Select, then hold L1 and press Circle(4), X, Circle(3) or Circle(4), X, Circle(4).

Replace all Pearls with Fish King coins
While playing on any level with Pearls, press Select, then hold L1 press Circle, X, Circle(3), X, Circle(2).

Completing dance mode
To complete dance mode easier, press X + Square + Circle + Triangle on each arrow; it will count as the arrow it is pointing to, even doubles.